Sleep habits and strategies of ultramarathon runners

<div><p>Among factors impacting performance during an ultramarathon, sleep is an underappreciated factor that has received little attention. The aims of this study were to characterize habitual sleep behaviors in ultramarathon runners and to examine strategies they use to manage sleep before and during ultramarathons. Responses from 636 participants to a questionnaire were considered. This population was found to sleep more on weekends and holidays (7–8 h to 8–9 h) than during weekdays (6–7 h to 7–8 h; p < 0.001). Work was a mediator of napping habits since 19–25% reported napping on work days and 37–56% on non-work days. There were 24.5% of the participants reporting sleep disorders, with more women (38.9%) reporting sleep problems than men (22.0%; p < 0.005). Mean (±SD) sleepiness score on the Epworth Sleepiness Scale was 8.9 ± 4.3 with 37.6% of respondents scoring higher than 10, reflecting excessive daytime sleepiness. Most of the study participants (73.9%) had a strategy to manage sleep preceding an ultramarathon, with 54.7% trying to increase their opportunities for sleep. Only 21% of participants reported that they had a strategy to manage sleep during ultramarathons, with micronaps being the most common strategy specified. Sub-analyses from 221 responses indicated that sleep duration during an ultramarathon was correlated with finish time for races lasting 36–60 h (r = 0.48; p < 0.01) or > 60 h (r = 0.44; p < 0.001). We conclude that sleep duration among ultramarathon runners was comparable to the general population and other athletic populations, yet they reported a lower prevalence of sleep disorders. Daytime sleepiness was among the lowest rates encountered in athletic populations, which may be related to the high percentage of nappers in our population. Sleep extension, by increasing sleep time at night and daytime napping, was the main sleep strategy to prepare for ultramarathons.</p></div

Sleep habits and strategies of ultramarathon runners - Fig 4

<p>Correlations between sleep duration and race time for races shorter than 36 h (panel A), races lasting between 36 and 60 h (panel B) and races longer than 60 h (panel C). No correlation was found between sleep duration and finish time for races ≤ 36 h (r = -0.05; p = 0.75), yet sleep duration and finish time were correlated for races lasting 36–60 h (r = 0.48; p < 0.01) or > 60 h (r = 0.44; p < 0.001).</p

Sleep strategies used during ultramarathons among subjects indicating they had slept during an ultramarathon.

<p>Sleep strategies used during ultramarathons among subjects indicating they had slept during an ultramarathon.</p

Percentage of participants with each ESS score range.

<p>Percentage of participants with each ESS score range.</p

Habitual sleep patterns for weekdays, weekends and holidays.

<p>Habitual sleep patterns for weekdays, weekends and holidays.</p

Use of substances affecting sleep.

<p>Use of substances affecting sleep.</p

Distribution of napping durations and reasons for not napping during the different training periods and during workdays and non-workdays.

<p>Distribution of napping durations and reasons for not napping during the different training periods and during workdays and non-workdays.</p

Sleep strategies used during the days and nights preceding an ultramarathon among subjects indicating they have pre-race sleep strategies.

<p>Most respondents selected multiple responses.</p

Image2.JPEG

<p>Recent research has shown that auditory closed-loop stimulation can enhance sleep slow oscillations (SO) to improve N3 sleep quality and cognition. Previous studies have been conducted in lab environments. The present study aimed to validate and assess the performance of a novel ambulatory wireless dry-EEG device (WDD), for auditory closed-loop stimulation of SO during N3 sleep at home. The performance of the WDD to detect N3 sleep automatically and to send auditory closed-loop stimulation on SO were tested on 20 young healthy subjects who slept with both the WDD and a miniaturized polysomnography (part 1) in both stimulated and sham nights within a double blind, randomized and crossover design. The effects of auditory closed-loop stimulation on delta power increase were assessed after one and 10 nights of stimulation on an observational pilot study in the home environment including 90 middle-aged subjects (part 2).The first part, aimed at assessing the quality of the WDD as compared to a polysomnograph, showed that the sensitivity and specificity to automatically detect N3 sleep in real-time were 0.70 and 0.90, respectively. The stimulation accuracy of the SO ascending-phase targeting was 45 ± 52°. The second part of the study, conducted in the home environment, showed that the stimulation protocol induced an increase of 43.9% of delta power in the 4 s window following the first stimulation (including evoked potentials and SO entrainment effect). The increase of SO response to auditory stimulation remained at the same level after 10 consecutive nights. The WDD shows good performances to automatically detect in real-time N3 sleep and to send auditory closed-loop stimulation on SO accurately. These stimulation increased the SO amplitude during N3 sleep without any adaptation effect after 10 consecutive nights. This tool provides new perspectives to figure out novel sleep EEG biomarkers in longitudinal studies and can be interesting to conduct broad studies on the effects of auditory stimulation during sleep.</p

Schematic representation of the kinematic variables measured at initial contact: foot-to-treadmill angle (FOOT), ankle angle (ANK) and tibia-to-treadmill angle (TIB).

<p>Schematic representation of the kinematic variables measured at initial contact: foot-to-treadmill angle (FOOT), ankle angle (ANK) and tibia-to-treadmill angle (TIB).</p